We can have an opinion, we can desire a certain outcome, but you are right, it ain't our fight.
Korea was engaged ostensibly to "stop the spread of communism" but I suspect it was taken on in order to gain another foothold, i e. military bases, in mainland Asia, airspace, and to aid financial recovery after WWII. Oddly, the US had been a founding member of the United Nations along with Communist Russia (USSR) and Communist China years prior to this conflict.
Doesn't sound too united does it?
Vietnam was France's fight with the communist takeover of Michelin rubber plantations later assumed by the US (for compensation?). Maintain a foothold in mainland Asia and airspace.
Iraq was to bring the puppet president of that country under control, or oust him, because after the US assisted him with his coup, he switched trade of his nation's oil from the US dollar to Euros. So, controlling oil, demanding obedience from their marionette, keeping the US dollar propped up, and a firm foothold, i.e. military bases, and airspace, in the middle east. The only "WMDs" Saddam ever had were provided him by the US.
Ukraine is to have excuse to sanction Russia and interfere with natural gas/oil sales. WHY - in retaliation for Russia's participation in the BRICS coalition which will trade commodities in each nation's currency instead of USD. This will cause the dollar substantial weakening. Also, friendly airspace. Not even going to conjecture on the purported US built and funded "Wuhan" type labs dotting Ukraine's border with Russia.
Israel is "saber rattling" on America's part in the hopes Iran does not become directly involved in the conflict. Eased oil sanctions on Iran bolster the USD and, again, maintaining a foothold in the middle east with friendly airspace. Israel can handle their business just fine on their own. Every war they've had since their state was established lasted only a matter of days.
I believe the citizens of the USA have had enough of their children being sent to foreign lands to come back injured physically and mentally, or dead. And for what? The same terrorists are terrorizing. The same issues arise as soon as troops are withdrawn.
Humanity be damned - Natural resources and the US Dollar. These are the US government's only concerns.